The following program demonstrates reading from two different input files. The idea is to switch between two 2-section scores, and write out the interleaved sections to a single output file.
#include "cscore.h" /* CSCORE_SWITCH.C */
cscore(CSOUND* cs) /* callable from either Csound or standalone cscore */
{
EVLIST *a, *b;
FILE *fp1, *fp2; /* declare two scorefile stream pointers */
fp1 = cscoreFileGetCurrent(cs); /* this is the command-line score */
fp2 = cscoreFileOpen(cs, "score2.srt"); /* this is an additional score file */
a = cscoreListGetSection(cs); /* read section from score 1 */
cscoreListPut(cs, a); /* write it out as is */
cscorePutString(cs, "s");
cscoreFileSetCurrent(cs, fp2);
b = cscoreListGetSection(cs); /* read section from score 2 */
cscoreListPut(cs, b); /* write it out as is */
cscorePutString(cs, "s");
cscoreListFreeEvents(cs, a); /* optional to reclaim space */
cscoreListFreeEvents(cs, b);
cscoreFileSetCurrent(cs, fp1);
a = cscoreListGetSection(cs); /* read next section from score 1 */
cscoreListPut(cs, a); /* write it out */
cscorePutString(cs, "s");
cscoreFileSetCurrent(cs, fp2);
b = cscoreListGetSection(cs); /* read next sect from score 2 */
cscoreListPut(cs, b); /* write it out */
cscorePutString(cs, "e");
}
Finally, we show how to take a literal, uninterpreted score file and imbue it with some expressive timing changes. The theory of composer-related metric pulses has been investigated at length by Manfred Clynes, and the following is in the spirit of his work. The strategy here is to first create an array of new onset times for every possible sixteenth-note onset, then to index into it so as to adjust the start and duration of each note of the input score to the interpreted time-points. This also shows how a Csound orchestra can be invoked repeatedly from a run-time score generator.
#include "cscore.h" /* CSCORE_PULSE.C */
/* program to apply interpretive durational pulse to */
/* an existing score in 3/4 time, first beats on 0, 3, 6 ... */
static float four[4] = { 1.05, 0.97, 1.03, 0.95 }; /* pulse width for 4's */
static float three[3] = { 1.03, 1.05, .92 }; /* pulse width for 3's */
cscore(CSOUND* cs) /* This example should be called from Csound */
{
EVLIST *a, *b;
EVENT *e, **ep;
float pulse16[4*4*4*4*3*4]; /* 16th-note array, 3/4 time, 256 measures */
float acc16, acc1,inc1, acc3,inc3, acc12,inc12, acc48,inc48, acc192,inc192;
float *p = pulse16;
int n16, n1, n3, n12, n48, n192;
/* fill the array with interpreted ontimes */
for (acc192=0.,n192=0; n192<4; acc192+=192.*inc192,n192++)
for (acc48=acc192,inc192=four[n192],n48=0; n48<4; acc48+=48.*inc48,n48++)
for (acc12=acc48,inc48=inc192*four[n48],n12=0;n12<4; acc12+=12.*inc12,n12++)
for (acc3=acc12,inc12=inc48*four[n12],n3=0; n3<4; acc3+=3.*inc3,n3++)
for (acc1=acc3,inc3=inc12*four[n3],n1=0; n1<3; acc1+=inc1,n1++)
for (acc16=acc1,inc1=inc3*three[n1],n16=0; n16<4; acc16+=.25*inc1*four[n16],n16++)
*p++ = acc16;
/* for (p = pulse16, n1 = 48; n1--; p += 4) /* show vals & diffs */
/* printf("%g %g %g %g %g %g %g %g\n", *p, *(p+1), *(p+2), *(p+3),
/* *(p+1)-*p, *(p+2)-*(p+1), *(p+3)-*(p+2), *(p+4)-*(p+3)); */
a = cscoreListGetSection(cs); /* read sect from tempo-warped score */
b = cscoreListSeparateTWF(cs, a); /* separate warp & fn statements */
cscoreListPlay(cs, b); /* and send these to performance */
a = cscoreListAppendStringEvent(cs, a, "s"); /* append a sect statement to note list */
cscoreListPlay(cs, a); /* play the note-list without interpretation */
for (ep = &a->e[1], n1 = a->nevents; n1--; ) { /* now pulse-modifiy it */
e = *ep++;
if (e->op == 'i') {
e->p[2] = pulse16[(int)(4. * e->p2orig)];
e->p[3] = pulse16[(int)(4. * (e->p2orig + e->p3orig))] - e->p[2];
}
}
cscoreListPlay(cs, a); /* now play modified list */
}